JP5839055B2 - Thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet.

Conventionally, a thermal transfer sheet in which a heat-melting ink layer (transferable colored layer) in which a colorant such as a pigment is dispersed in a binder such as a heat-meltable wax or resin is supported on a base sheet such as a plastic film is used. In addition, there is known a hot-melt transfer method in which energy corresponding to image information is applied to a heating device such as a thermal head and a colorant is transferred onto a transfer paper such as paper or a plastic sheet together with a binder (Patent Document 1). . An image formed by the hot-melt transfer method has high density and excellent sharpness, and is suitable for recording binary images such as characters and line drawings. Further, by using a thermal transfer sheet of yellow, magenta, cyan, black or the like and recording it on a transfer paper, it is possible to form a multicolor or color image.
In such a hot-melt transfer method, various types of printing can be easily formed with a thermal head, etc., so that characters and barcodes can be printed for managing products at factories and the like. It's being used.

In addition, in the thermal transfer sheet used in the hot melt transfer method, a release layer is provided on the surface of the base sheet on the hot melt ink layer side in order to improve the peelability when transferring the transferable colored layer. In order to improve the durability of the transferable colored layer, a transferable protective layer provided on the surface of the transferable colored layer on the substrate sheet side is known.
For example, in Patent Document 2, for the purpose of providing a thermal transfer recording medium from which a transfer image excellent in scratch resistance, friction resistance, hot press resistance and heat resistance can be obtained, a thermoplastic resin, A thermal transfer recording medium comprising a thermal transfer layer mainly composed of a surfactant and a colorant having a melting point of 30 to 60 ° C. and an HLB value of 3 to 12 is disclosed, and the thermal transfer recording medium Describes that a release layer mainly composed of a wax having a melting point or a softening point of 50 to 130 ° C. can be provided between the support and the thermal transfer layer.

JP-A-57-105395 JP-A-3-234586

On the other hand, it is obtained when printing is performed by a hot melt transfer method using a thermal transfer sheet on a packaging material that is subjected to a boil sterilization process after packaging food or a plastic film that is used as a packaging material for retort food. In addition, boil resistance is required so that the printed matter is not lost even if it is stirred in boiling hot water.
The present invention has been accomplished in view of the above circumstances, and an object of the present invention is to provide a thermal transfer sheet excellent in boil resistance and printability of printed matter.

In the thermal transfer sheet according to the present invention, at least a transferable release layer and a transferable colored layer are arranged in this order from one side of the substrate, and a back layer is arranged on the other side of the substrate. And
The transferable release layer includes a wax having a melting point of 65 ° C. or more and a metal soap, the average particle diameter of the metal soap is 0.1 to 2.0 μm, and the content of the metal soap is the transfer 15 to 25% by mass with respect to the total solid content contained in the adhesive release layer,
Said transferable color layer seen containing a colorant and a softening point 100 ° C. or more phenolic resins,
A transferable protective layer is further disposed between the transferable release layer and the transferable colored layer, and the transferable protective layer protects the cyclic olefin polymer having a glass transition temperature of 100 ° C. or higher. It is contained in excess of 50% by mass of the solid content of the layer, and further contains an incompatible resin for the cyclic olefin polymer .

In the thermal transfer sheet according to the present invention, the content of the metal soap, because it is 15-25% by weight based on the total solids contained in the transferable peeling layer, resistance to boiling of the printed product, and printing Ru excellent sex.

In the thermal transfer sheet according to the present invention, a transferable protective layer is further disposed between the transferable release layer and the transferable colored layer, and the transferable protective layer has an annular shape having a glass transition temperature of 100 ° C. or higher. include olefin polymer at 50 wt% excess of the solid content of the transferable protective layer, since it further comprises a non-compatible resin with respect to the cyclic olefin polymer, anti-boiling of the printed product, and scratch resistance It is preferable from the viewpoint of superiority.

  In the thermal transfer sheet according to the present invention, the metal soap is preferably zinc stearate from the viewpoint of excellent boil resistance of printed matter.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal transfer sheet excellent in the boil resistance of printed matter and printability can be provided.

It is a schematic sectional drawing which shows an example of the thermal transfer sheet of this invention. It is a schematic sectional drawing which shows another example of the thermal transfer sheet of this invention.

In the thermal transfer sheet according to the present invention, at least a transferable release layer and a transferable colored layer are arranged in this order from one side of the substrate, and a back layer is arranged on the other side of the substrate. And
The transferable release layer includes a wax having a melting point of 65 ° C. or higher and a metal soap,
The transferable colored layer is a thermal transfer sheet containing a colorant and a phenol resin having a softening point of 100 ° C. or higher.

The thermal transfer sheet according to the present invention contains a phenol resin having a softening point of 100 ° C. or higher as the binder resin of the transferable colored layer, and the transferable release layer contains a wax having a melting point of 65 ° C. or higher and a metal soap. As a result, the printability is excellent, but the boil resistance of the printed matter is excellent.
Although the mechanism by which the thermal transfer sheet according to the present invention exhibits the above effects has not been elucidated, it is presumed as follows. The phenol resin has good adhesion to a plastic film used as a packaging material, and improves the printability. Further, by using a phenol resin having a softening point of 100 ° C. or higher, transfer of a very fine character pattern is also improved. For example, a 1-dot character pattern printability is excellent with a thermal head having a resolution of 300 dpi. Furthermore, excellent heat resistance is imparted to the printed matter by selecting a phenol resin having a softening point of 100 ° C. or higher as the phenol resin.
However, when the colored layer is the outermost layer in the printed matter, the boil resistance becomes insufficient due to rubbing at the time of boiling. On the other hand, when printing is performed using the thermal transfer sheet according to the present invention, the transferable release layer is peeled off from the substrate, and the transferable release layer is laminated and transferred onto the transferable colored layer. The transferable release layer is provided on the outer layer. When the transferable peeling layer contains the wax having the specific melting point and the metal soap, the boil resistance of the printed matter is improved in the present invention. When only the wax is used for the transferable release layer, the boilability is still insufficient even when the outermost layer of the printed matter becomes the release layer. This is presumably because the wax melts and flows out during boiling. On the other hand, when the wax having the specific melting point and the metal soap are combined, it is considered that the metal soap functions to block out the outflow of the wax in the transferable peeling layer melted at the time of boiling. It is estimated that the outflow of wax is suppressed. Furthermore, since the metal soap has excellent affinity with wax, it has heat resistance and excellent slipperiness, so even if the surface of the printed material is rubbed during boiling, it is difficult to drop off and has excellent boil resistance. It is estimated to be.
Thus, the thermal transfer according to the present invention is achieved by the synergistic effect of the combination of the transferable colored layer containing a phenol resin having a softening point of 100 ° C. or higher and the transferable release layer containing a wax having a melting point of 65 ° C. or higher and a metal soap. The sheet is excellent in boil resistance and printability of printed matter.

FIG. 1 shows an example of the thermal transfer sheet of the present invention. The thermal transfer sheet 10 of FIG. 1 has a transferable release layer 2 and a transferable colored layer 3 arranged in this order on one surface of the substrate 1 from the substrate 1 side, and the back surface on the other surface of the substrate 1. The layer 4 is arranged.
FIG. 2 shows another example of the thermal transfer sheet of the present invention. In the thermal transfer sheet 10 of FIG. 2, a transferable release layer 2, a transferable protective layer 5, and a transferable colored layer 3 are arranged in this order on one surface of the substrate 1 from the substrate 1 side. This is a configuration in which the back layer 4 is disposed on the other surface.
In the thermal transfer sheet according to the present invention, as shown in FIGS. 1 and 2, each of the above layers has a laminated structure.
Hereinafter, each layer constituting the thermal transfer sheet of the present invention will be described in detail.

(Base material)
The substrate 1 of the thermal transfer sheet used in the present invention is not particularly limited as long as it has a conventionally known degree of heat resistance and strength.
Specific examples of the base material include, for example, polyesters such as polyethylene terephthalate, 1,4-polycyclohexylenedimethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polysulfone, polycarbonate, polyamide, polyimide, cellulose acetate, polyvinylidene chloride, There are resin base materials such as polyvinyl chloride, polyvinyl alcohol, polystyrene, fluororesin, polypropylene, polyethylene, and ionomer, and papers such as glassine paper, condenser paper, paraffin paper, cellophane, etc. A laminated composite substrate can also be used. Moreover, in the case of the said resin base material, it may consist only of 1 type of the above-mentioned resin, and may consist of 2 or more types of resin.
The thickness of these base materials may be appropriately changed depending on the material so that the strength and heat resistance thereof are appropriate, but is usually preferably about 0.5 to 50 μm, more preferably about 1 to 10 μm. is there.

(Transferable release layer)
The transferable release layer 2 contains at least a wax having a melting point of 65 ° C. or higher and a metal soap. The thermal transfer sheet according to the present invention is excellent in the peelability of the layer to be transferred at the time of thermal transfer by the transferable release layer, and the printed matter obtained using the thermal transfer sheet according to the present invention is the same as the transferable release layer. Boil resistance is excellent due to interaction with a specific transferable colored layer described later.

Examples of the wax having a melting point of 65 ° C. or higher include, for example, microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, silicone wax, various low molecular weight polyethylenes, wood wax, beeswax, whale wax, ibota wax, wool wax, shellac wax, Candelilla wax, petrolactam, partially modified wax, fatty acid ester, fatty acid amide and the like can be mentioned. In the present invention, carnauba wax having strong scratch resistance is preferably used.
In addition, the said wax may be used individually by 1 type, and may mix and use 2 or more types.

  The content of the wax having a melting point of 65 ° C. or higher is not particularly limited, but is preferably 60 to 85% by mass, and 70 to 85% by mass with respect to the total solid content contained in the transferable release layer. More preferably. When the content is not less than the lower limit, the peelability of the transferable release layer from the substrate is improved, and when it is not more than the upper limit, the boil resistance is improved. In addition, in this invention, solid content represents all components other than a solvent.

  Examples of the metal soap include alkali metal salts such as fatty acid, rosin acid, and naphthenic acid, alkaline earth metal salts, and metal salts such as aluminum and zinc, and in particular, alkaline earth metal salts of fatty acids. Aluminum salts or zinc salts are preferred. Examples of fatty acids used in metal soaps include butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid. Specific examples include barium stearate, lithium stearate, calcium stearate, zinc stearate, aluminum stearate, magnesium stearate and the like. Among these, from the viewpoint of boil resistance, a magnesium salt, a zinc salt or an aluminum salt is preferable, a zinc salt is more preferable, and zinc stearate is still more preferable. A metal soap may be used individually by 1 type, and 2 or more types may be mixed and used for it.

The average particle diameter of the metal soap is not particularly limited, but is preferably 0.1 to 2.0 μm, and more preferably 0.5 to 1.5 μm from the viewpoint of printability.
The average particle diameter is a 50% particle diameter (d50 median diameter) when the particle diameter distribution measured by the laser diffraction scattering method is represented by a volume cumulative distribution. As a specific measuring apparatus, for example, a laser diffraction / scattering particle size distribution measuring apparatus manufactured by HORIBA, Ltd. can be exemplified. The average particle size is the average particle size of the primary particle size if the metal soap does not aggregate, and the average particle size of the secondary particle size when the metal soap is aggregated particles.

  Although melting | fusing point of the said metal soap is not specifically limited, From the point which is excellent in boil resistance, it is preferable that it is 90 degreeC or more, and it is more preferable that it is 100 degreeC or more.

  Although content of the said metal soap is not specifically limited, It is preferable that it is 10-40 mass% with respect to the total solid contained in a transferable peeling layer, and it is more preferable that it is 15-30 mass%. More preferably, it is 15-25 mass%. When the content of the metal soap is equal to or higher than the lower limit value, the boil resistance of the printed matter is improved, and when the content is equal to or lower than the upper limit value, the printability of the thermal transfer sheet, particularly the print sensitivity is improved.

Moreover, the transferable peeling layer 2 may contain other materials as necessary within a range not impeding the effects of the present invention. Examples of other materials include organic fine particles such as acrylic fine particles, polyamide fine particles, fluorine fine particles, and polyethylene wax; inorganic materials such as talc, kaolin, clay, calcium carbonate, magnesium hydroxide, magnesium carbonate, magnesium oxide, and silica. Fine particles: silicone resin, fluorine resin, acrylic resin, polyvinyl alcohol resin, cellulose derivative resin, urethane resin, acetic acid vinyl resin, acrylic vinyl ether resin, maleic anhydride resin, melamine resin, polyolefin resin, ionomer resin, styrene resin, Examples of these resins include copolymers.
The transferable release layer 2 may contain a wax having a melting point of less than 65 ° C., but the content of the wax having a melting point of less than 65 ° C. is included in the transferable release layer from the viewpoint of boil resistance. The total solid content is preferably 5% by mass or less.

The transferable peeling layer 2 is a gravure coat, a gravure reverse coat, a knife coat, an air coat, a coating solution to which the wax having a melting point of 65 ° C. or higher, the metal soap, and, if necessary, the other materials and a solvent are added. It can be formed by applying by conventional coating means such as roll coating and die coating and drying.
As said solvent, what can disperse | distribute or melt | dissolve the material mentioned above can be selected suitably, For example, aromatic solvents, such as ketone solvents, such as methyl ethyl ketone, toluene, these mixed solvents, etc. are mentioned. It is done.

The coating amount of transferable peeling layer is a 0.5 g / ^{m 2} approximately in the normal drying, preferably 0.1g ^{/ m 2} ~1.0g ^/ m 2 in dry. If it is less than 0.1 g / m ² , the peelability may deteriorate and the effect of the transferable release layer may not be obtained. On the other hand, if it exceeds 1.0 g / m ² , transfer for each release layer is likely to occur, and the transferability of the layer to be transferred may be deteriorated.

(Transferable colored layer)
The transferable colored layer 3 contains at least a colorant and a phenol resin having a softening point of 100 ° C. or higher as a binder resin. By using a phenol resin having a softening point of 100 ° C. or higher as the binder resin of the transferable colored layer, the printability is improved while having heat resistance.

Examples of the phenol resin having a softening point of 100 ° C. or higher used in the transferable colored layer of the present invention include a phenol novolak resin, a cresol novolak resin, a bisphenol novolak resin, a biphenylene aralkyl resin, a naphthol aralkyl resin, and a phenol aralkyl resin (also known as xylylene-modified). Phenolic resins) and the like, and one or more of these may be used in combination. Among these, from the viewpoint of the balance between printability and boil resistance, it is preferable to use a phenol novolak resin, a cresol novolak resin, or a bisphenol novolak resin, and more preferably a phenol novolak resin.
The softening point of the phenol resin is 100 ° C. or higher from the viewpoint of boil resistance, but is preferably 110 ° C. or higher.
In addition, the softening point of the phenol resin in this invention means the softening point measured by the method prescribed | regulated to JISK7206: 1999.

  Examples of commercially available phenol resins having a softening point of 100 ° C. or higher include Phenolite TD-2091, Phenolite TD-2090, Phenolite VH4170, Phenolite KH6021, Phenolite KA1163, Phenolite KA1165 (and above, DIC Corporation). Manufactured) and the like.

  As a binder resin for the transferable colored layer, a phenol resin having a softening point of 100 ° C. or higher may be used in combination with a curing agent, and a reaction product of the phenol resin and the curing agent may be included. By cross-linking the phenol resin with a curing agent, a three-dimensional network structure can be constructed, and excellent heat resistance can be imparted to the printed matter. Examples of the curing agent include formaldehyde supply compounds such as hexamethylenetetramine and paraformaldehyde, polyisocyanate compounds, and the like. In the present invention, a polyisocyanate compound is preferably used as a curing agent combined with a phenol resin having a softening point of 100 ° C. or higher.

  In the transferable colored layer of the present invention, the equivalent ratio (NCO / OH) of the isocyanate group of the polyisocyanate compound to the hydroxyl group of the phenol resin having the softening point of 100 ° C. or higher is preferably from the viewpoint of good printability. It is preferable to use a combination of a phenol resin and an isocyanate compound so as to be in the range of 05 to 0.5 and further in the range of 0.1 to 0.25.

  In the present invention, the polyisocyanate compound used as a curing agent for the phenol resin can be appropriately used as long as it is a compound having two or more isocyanate groups in the molecule. For example, aromatic polyisocyanates such as tolylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; modified polyisocyanates such as adduct, biuret and isocyanurate Can be mentioned.

  In the present invention, the polyisocyanate compound used as a curing agent for the phenol resin is preferably an aliphatic polyisocyanate from the viewpoint of further improving the boil resistance, and among them, an adduct of an aliphatic polyisocyanate is used. It is preferable. By including a reaction product of a phenol resin having a softening point of 100 ° C. or higher and an adduct of an aliphatic polyisocyanate as a binder resin for the transferable colored layer, the boil resistance of the printed matter is good. Will be particularly good. When a curing agent is used in the phenolic resin, a three-dimensional network structure is built, and excellent heat resistance is imparted to the printed matter. At that time, when an aliphatic polyisocyanate is selected and combined, the three-dimensional phenolic resin is added. This is not because the network structure is flexible and the printed matter on the packaging material is affected by deformation such as shrinkage and expansion of the packaging material in boiling water. It is estimated that.

  Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, trimethylhexamethylene diisocyanate, and the like. Is preferably used.

  The adduct body is a reaction product of polyisocyanate and polyol. As the polyol used in the adduct body, alcohol having two or more hydroxyl groups in the molecule is used, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, Examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, and dimers thereof, polyester polyol, polycarbonate polyol, polyether polyol, and polyolefin polyol. As the polyol used for the adduct, alcohol having 3 or more hydroxyl groups in the molecule is preferably used from the viewpoint of boil resistance, and glycerin, trimethylolpropane, and trimethylolethane are particularly preferably used.

  The mass average molecular weight of the adduct of the aliphatic polyisocyanate is usually selected in the range of 100 to 100,000, preferably 500 to 10,000 from the viewpoint of boil resistance. In the present invention, the mass average molecular weight is a value calculated as a polystyrene equivalent value by gel permeation chromatography (GPC method).

As the binder resin in the transferable colored layer of the present invention, another binder resin may be further contained within a range not impeding the effects of the present invention. For example, as other binder resin, acrylic resin, polyester resin, polyurethane resin, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyethylene, polystyrene, polypropylene, polybudene, petroleum resin, vinyl chloride resin, Vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, vinylidene chloride resin, methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl formal, polyvinyl butyral, acetyl cellulose, nitrocellulose, polyvinyl acetate, polyisobutylene, ethyl cellulose, polyacetal, etc. Is mentioned.
As the binder resin in the transferable colored layer of the present invention, from the viewpoint of boil resistance, a phenol resin (solid content) having a softening point of 100 ° C. or higher may be contained by 20% by mass or more in the solid content of all binder resins. Preferably, it is further contained in an amount of 30% by mass or more, more preferably 40% by mass or more, and particularly preferably 50% by mass or more.
When a curing agent is used, a reaction product of a phenol resin having a softening point of 100 ° C. or higher and a curing agent, an unreacted phenol resin having a softening point of 100 ° C. or higher and an unreacted curing that may be further included. The total solid content with the agent is preferably 70% by mass or more of the total solid content of the binder resin, more preferably 80% by mass or more, and still more preferably 90% by mass or more, In particular, it is preferably contained at 95% by mass or more.
From the viewpoint of further improving the boil resistance, the binder resin in the transferable colored layer of the present invention is composed of two components of a solid resin, a phenol resin having a softening point of 100 ° C. or higher, and an adduct body of aliphatic polyisocyanate. The aspect which consists only of the hardened | cured material of the resin composition which becomes is used suitably.

The colorant used in the transferable colored layer of the present invention can be appropriately selected from carbon black, inorganic pigments, organic pigments or dyes according to the required color tone. For example, in the case of barcode printing, it is particularly preferable to have a sufficiently black density and not discolor or fade by light, heat or the like. Examples of such a colorant include carbon black such as lamp black, graphite, and nigrosine dye. When color printing is required, other chromatic dyes or pigments are used. Furthermore, in order to give good thermal conductivity and antistatic properties within a range where the melt viscosity is not significantly increased, a carbonaceous material such as carbon black, or a heat conductive or conductive material such as metal powder can be blended.
Further, the transferable colored layer may further contain other components as long as the effects of the present invention are not hindered. For example, additives such as inorganic fine particles, organic fine particles, and a release agent may be contained.

In the transferable colored layer of the present invention, the mixing ratio of the colorant and the binder resin is not particularly limited, but the colorant is usually used at 20 to 70% by mass in the total solid content of the transferable colored layer. It is preferable to be used at 30 to 50% by mass.
The binder resin is preferably used in an amount of 30 to 80% by mass and more preferably 50 to 70% by mass in the total solid content of the transferable colored layer from the viewpoint of printability and boil resistance. preferable.

The transferable colored layer can be formed by applying a coating solution in which the above-described materials are dispersed or dissolved in an organic solvent or the like by a conventionally known coating means and drying.
The coating amount of the transfer the colored layer is not particularly limited, but 0.6 g / ^{m 2} approximately in the normal drying, preferably 0.4g ^{/ m 2} ~3.0g ^/ m 2 in dry. If it is less than 0.4 g / m ² , the transfer printing density may be lowered, and if it is more than 3.0 g / m ² , the heat melting property of the film may be lowered, and thermal transfer may be difficult to occur. .

(Transferable protective layer)
As shown in FIG. 2, the thermal transfer sheet of the present invention is provided with a transferable protective layer 5 between the substrate 1 and the transferable colored layer 3 in order to further improve the durability of the transferable colored layer. Also good. The transferable protective layer is transferred together with the transferable colored layer 2 during thermal transfer and covers the surface of the transferred image.

The transferable protective layer is preferably formed by appropriately selecting a resin that forms a tough film having high durability such as heat resistance, friction resistance, and boil resistance. Resin that forms a tough coating with high durability, such as acrylic resin such as polymethylmethacrylate resin, polyurethane resin, polyester resin, polyamide resin, chlorinated polypropylene, etc., toughness such as heat resistance and friction resistance It can form from resin which forms a film. In addition, a resin that does not melt with heat after the coating is formed, for example, a thermosetting resin, a resin that is cross-linked and cured by a cross-linking agent, for example, an acrylic polyol, a phenol resin, and the like.
In the present invention, the transferable protective layer includes, in particular, a cyclic olefin polymer having a glass transition temperature of 100 ° C. or higher as a main component from the viewpoint of further improving the boil resistance of the printed matter. It is preferable that the resin contains an incompatible resin for the polymer. Here, the main component means that the cyclic olefin polymer is contained in an amount exceeding 50% by mass of the solid content of the transferable protective layer. The cyclic olefin polymer is more preferably 70% by mass or more of the solid content of the transferable protective layer, and still more preferably 80% by mass or more of the solid content of the transferable protective layer.

The cyclic olefin polymer used in the present invention represents a polymer having a structural unit derived from a monomer comprising a cyclic olefin. That is, the cyclic olefin polymer has a cyclic structure in the main chain.
Specifically, the cyclic olefin polymer used in the present invention may be a cyclic olefin polymer or copolymer obtained by ring-opening polymerization of a cyclic olefin, and a cyclic olefin, a chain olefin, and a vinyl group. It may be a cyclic olefin copolymer obtained by addition polymerization with one or more selected from the aromatic compounds possessed, and some or all of them may be hydrogenated. In the cyclic olefin-based polymer, the cyclic olefin may be used alone or in combination of two or more.
The type of copolymerization is not limited in the present invention, and various known copolymerization types such as random copolymer, block copolymer, and alternating copolymerization can be applied.

The cyclic olefin used in the ring-opening polymerization or addition polymerization is preferably a polycyclic cyclic olefin, and more preferably a norbornene-based monomer having a norbornene ring structure. Examples of the norbornene-based monomer include bicyclo [2.2.1] hept-2-ene (common name: norbornene), 5-ethylidene-bicyclo [2.2.1] hept-2-ene (common name: ethylidene). Norbornene) and its derivatives (having substituents in the ring); tricyclo [4.3.0 ^1,6 . 1 ^2,5 ] deca-3,7-diene (common name dicyclopentadiene) and its derivatives and other tricyclic monomers; 7,8-benzotricyclo [4.3.0.1 ^2,5 ] Deca-3-ene (common name methanotetrahydrofluorene: also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene) and its derivatives, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (common name: tetracyclododecene), 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene and tetracyclic monomers such as derivatives thereof; and the like.
Examples of the substituent that the derivative has include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, an alkylidene group, a cyano group, and a halogenated alkyl group. Specific examples of the derivative include 8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene and the like.

Examples of the chain olefin used in the addition polymerization type cyclic olefin copolymer include α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene and 4-methyl. Examples include -1-pentene, 1-hexene, 1-octene, and 1-decene. Specific examples of the aromatic compound having a vinyl group include styrene, vinyl naphthalene, methyl styrene, propyl styrene, cyclohexyl styrene, dodecyl styrene, 2-ethyl-4-benzyl styrene, 4- (phenylbutyl) styrene, m-divinylbenzene, p-divinylbenzene, bis (4-vinylphenyl) methane and the like can be mentioned.
The chain olefin and the aromatic compound having a vinyl group can be used alone or in combination of two or more.

As the cyclic olefin polymer used in the present invention, a cyclic olefin polymer having a glass transition temperature (Tg) of 100 ° C. or higher is used from the viewpoint of excellent boil resistance. Especially, it is preferable that the glass transition temperature (Tg) of a cyclic olefin polymer is 140 degreeC or more from the point which improves boil resistance. If the glass transition temperature is high, the number of cyclic olefin-derived repeating units tends to increase, and it is estimated that heat resistance is improved and water absorption is further reduced.
On the other hand, the glass transition temperature (Tg) of the cyclic olefin polymer is preferably 200 ° C. or less from the viewpoint of printability. If the glass transition temperature is too high, it is presumed that the thermal response is hindered.
In addition, the glass transition temperature (Tg) in this invention is a temperature calculated | required based on the measurement (DSC method) of the calorie | heat amount change by DSC (differential scanning calorimetry).

  The cyclic olefin polymer used in the present invention is more preferably a cyclic olefin polymer having a structural unit represented by the following general formula (1) from the viewpoint of heat resistance and flexibility.

〔式中、Ａ^１、Ａ^２、Ａ^３およびＡ^４は、それぞれ独立に、水素原子、炭素数１〜１０の炭化水素基、ハロゲン原子、ハロゲン原子で置換された炭素数１〜１０の炭化水素基、−（ＣＨ_２）_ｎＣＯＯＲ^１、−（ＣＨ_２）_ｎＯＣＯＲ^１、−（ＣＨ_２）_ｎＯＲ^１、−（ＣＨ_２）_ｎＣＮ、−（ＣＨ_２）_ｎＣＯＮＲ^３Ｒ^２、−（ＣＨ_２）_ｎＣＯＯＺ、−（ＣＨ_２）_ｎＯＣＯＺ、−（ＣＨ_２）_ｎＯＺ、−（ＣＨ２）_ｎＷ、またはＡ^２とＡ^３から構成された−ＯＣ−Ｏ−ＣＯ−、−ＯＣ−ＮＲ^４−ＣＯ−、もしくは（多）環状アルキレン基を示す。ここでＲ^１、Ｒ^２、Ｒ^３およびＲ^４は、炭素数１〜２０の炭化水素基、Ｚはハロゲン原子で置換された炭化水素基、ＷはＳｉＲ^５ _ｐＦ_３−ｐ（Ｒ^５は炭素数１〜１０の炭化水素基、Ｆはハロゲン原子、−ＯＣＯＲ^６または−ＯＲ^６（Ｒ^６は炭素数１〜１０の炭化水素基）、ｐは０〜３の整数を示す）、ｎは０〜１０の整数を示す。〕

[Wherein, A ¹ , A ² , A ³ and A ⁴ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, or a carbon atom having 1 to 10 carbon atoms substituted with a halogen atom. hydrogen ^{_{radical, - (CH 2) n COOR}} 1, - (CH 2) n OCOR 1, - (CH 2) n OR 1, - (CH 2) n CN, - (CH 2) n CONR 3 R 2, - _{(CH 2) n COOZ, -} (CH 2) n OCOZ, - (CH 2) n OZ, - (CH2) n W, or ^{A 2} and ^{A 3} from the configured -OC-O-CO -, - OC —NR ⁴ —CO— or (poly) cyclic alkylene group is shown. Here, R ¹ , R ² , R ³ and R ⁴ are each a hydrocarbon group having 1 to 20 carbon atoms, Z is a hydrocarbon group substituted with a halogen atom, W is SiR ⁵ _p F _3-p (R ⁵ is A hydrocarbon group having 1 to 10 carbon atoms, F is a halogen atom, -OCOR ⁶ or -OR ⁶ (R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms), p is an integer of 0 to 3), and n is An integer of 0 to 10 is shown. ]

In the cyclic olefin polymer having the structural unit represented by the general formula (1), among them, any of A ¹ , A ² , A ³ and A ⁴ has a cyclic olefin polymer having a substituent containing oxygen. The combination is preferable from the viewpoint of interlayer adhesion with the transferable colored layer. Examples of the substituent containing oxygen include the above-described — (CH ₂ ) _n COOR ¹ , — (CH ₂ ) _n OCOR ¹ , — (CH ₂ ) _n OR ¹ , — (CH ₂ ) _n CONR ³ R ² , — ( CH ₂ ) _n COOZ, — (CH ₂ ) _n OCOZ, — (CH ₂ ) _n OZ, or —OC—O—CO—, —OC—NR ⁴ —CO—, etc. composed of A ² and A ³ Among them, — (CH ₂ ) _n COOR ¹ or — (CH ₂ ) _n OCOR ¹ is preferable.

  The cyclic olefin polymer used in the present invention is an amorphous polyolefin resin and preferably has a mass average molecular weight in the range of 50,000 to 300,000.

The cyclic olefin polymer can be synthesized by ring-opening polymerization or addition polymerization of a cyclic olefin by a conventionally known method, and further hydrogenating as necessary. Or you may use a commercial item.
Examples of commercially available addition polymerization type cyclic olefin polymers include Apel manufactured by Mitsui Chemicals and TOPAS manufactured by Polyplastics. Examples of commercially available ring-opening polymerization type cyclic olefin polymers include ZEONEX manufactured by Nippon Zeon Co., Ltd. and ARTON manufactured by JSR Corporation.

On the other hand, the incompatible resin for the cyclic olefin polymer used in combination with the cyclic olefin polymer may be an incompatible resin that does not completely dissolve in the cyclic olefin polymer used in combination. If it does not specifically limit. The incompatibility is determined according to a conventional method in the resin industry. For example, a composition obtained by melting and mixing 5 parts by mass of a resin with respect to 100 parts by mass of a cyclic olefin polymer is magnified 100,000 times with an electron microscope, and a domain of 1 mm ² or more in a range of 10 cm × 15 cm or Those having at least one particle can be defined as incompatible.

  As the incompatible resin, other resins than the cyclic olefin polymer are usually used. Examples of other resins that are incompatible with norbornene resins include polyethers or polythioethers such as polyphenylene sulfide and polyphenylene ether; aromatic polyesters, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyether ketone. Polyester polymers; Chain polyolefin polymers such as polyethylene, polypropylene, and poly-4-methyl-pentene-1; General-purpose transparent resins such as polyacrylonitrile styrene (AS resin); Cyclic olefins such as acrylic resins A resin that is incompatible with the polymer is appropriately selected and used. Among these, a polyol having a hydroxyl group is preferably used, and examples thereof include polyester polyol, polycarbonate polyol, polyether polyol, polyolefin polyol, and acrylic polyol.

  When an incompatible resin is added with a cyclic olefin polymer as a main component, a large number of dispersed microdomains or particles of the incompatible resin are formed in a coating film formed by coating the incompatible resin. From the viewpoint of improving the transparency of the transferable protective layer and the transferability of the transferable protective layer, the microdomain has an average particle diameter [(major axis + minor axis) / 2] observed with an electron microscope, The size is preferably 5 to 30 μm, more preferably 10 to 20 μm.

Since the boil resistance of the transferable protective layer, transparency, and transferability of the transferable protective layer can be exhibited in a balanced manner, the incompatible resin is the cyclic olefin polymer in the transferable protective layer. And 5 to 30 parts by mass, preferably 10 to 25 parts by mass, based on 100 parts by mass of the total amount of the incompatible resin.
If the amount of the incompatible resin is less than the above ratio, the film cutting property at the time of transfer is deteriorated, and the printability may be deteriorated. On the other hand, when there are too many said incompatible resins than the said ratio, there exists a possibility that application | coating suitability may deteriorate or boil resistance may deteriorate.

Moreover, as a transferable protective layer, in addition to the above-mentioned thermoplastic resin, a lubricant component such as metal soap, phosphate ester, polyethylene wax, talc, silicone resin fine particles and the like, and an auxiliary to lubricity are provided for the purpose of improving slip properties. For the purpose of adjustment, it is preferable that various additives such as inorganic or organic fine particles or silicone oil are contained, and it is particularly preferable that lubricant components such as polyethylene wax, talc, and silicone resin fine particles are contained. preferable.
When the lubricant component is contained in the transferable protective layer, the content of the lubricant component is preferably 1 to 20% by mass in the solid content of the transferable protective layer.

The coating amount of the transferable protective layer, so that the film breakage is sufficiently performed, so that a thin layer is preferably 0.1g ^{/ m 2} ~1.5g ^/ m 2 in dry. Further, in order to improve the film breakage, a transferable protective layer may be formed by adding a fine extender pigment such as silica, alumina, clay, calcium carbonate or the like.

(Back layer)
In the thermal transfer sheet of the present invention, a back layer is provided on the other surface of the substrate in order to prevent adverse effects such as sticking and printing wrinkles due to heat from a thermal head, a transfer hot plate or the like.
The back layer can be formed by appropriately selecting a conventionally known thermoplastic resin or the like. As such a thermoplastic resin, for example, polyester resins, polyacrylate resins, polyvinyl acetate resins, styrene acrylate resins, polyurethane resins, polyethylene resins, polypropylene resins, and other polyolefin resins, Polystyrene resin, polyvinyl chloride resin, polyether resin, polyamide resin, polyimide resin, polyamideimide resin, polycarbonate resin, polyacrylamide resin, polyvinyl chloride resin, polyvinyl butyral resin, polyvinyl acetoacetal resin, etc. Polyvinyl acetal resins, polyvinyl alcohol resins, ethyl cellulose resins, thermoplastic resins such as cellulose resins such as methyl cellulose resins, these silicone-modified products, and fluorine-modified polyurethane Resins.

  Moreover, you may add a crosslinking agent to above-described resin. As the polyisocyanate resin functioning as a cross-linking agent, conventionally known ones can be used without any particular limitation. Among them, it is desirable to use an adduct of an aromatic polyisocyanate. Examples of the aromatic polyisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, and tolidine diisocyanate. , P-phenylene diisocyanate, trans-cyclohexane-1,4-diisocyanate, xylylene diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) thiophosphate, and the like. Particularly, 2,4-toluene diisocyanate, 2,6- Toluene diisocyanate or a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate is preferred.

  In addition to the above thermoplastic resin, the back layer is provided with a lubricant component such as metal soap, phosphate ester, polyethylene wax, talc, and silicone resin fine particles in addition to the thermoplastic resin, and an auxiliary to the slipperiness. For adjustment, it is preferable that various additives such as inorganic or organic fine particles or silicone oil are contained, and it is particularly preferable that at least one of phosphate ester or metal soap is contained. Moreover, you may contain electroconductive carbon for antistatic.

The back layer is, for example, a coating solution obtained by dispersing or dissolving the thermoplastic resin and various additives added as necessary in a suitable solvent by a conventionally known gravure coating, gravure reverse coating, or the like. It can be formed by drying.
The coating amount of the back layer is not particularly limited, from the viewpoint of improvement of heat resistance and the like, preferably 0.01g ^{/ m 2} ~0.2g ^/ m 2 in dry.
Moreover, in order to improve the adhesiveness of a back surface layer and a base material, or to further reduce the damage by the heat | fever of the thermal head which a base material sheet receives, you may provide further a back surface primer layer.

  The transfer material printed by the thermal transfer sheet of the present invention is not particularly limited and may be any material such as general paper, barcode label paper, synthetic paper, plastic film, sheet, metal, wood, glass, resin molded product, and the like. However, since the thermal transfer sheet of the present invention is particularly excellent in boil resistance, it is particularly suitable for a packaging material that is subjected to a boil sterilization process after packaging food or a plastic film used as a packaging material for retort food. Preferably used. Examples of the packaging material as described above include various laminated films. For example, the surface to be printed includes nylon, and laminated films made of a plastic film mainly composed of a polyester resin such as polyethylene terephthalate. It is not limited to.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. These descriptions do not limit the present invention. In the text, “part” or “%” is based on mass unless otherwise specified. Moreover, the average particle diameter of the metal soap was measured using a laser diffraction / scattering particle size distribution measuring apparatus LA-920 manufactured by Horiba.
(Example 1: Production of thermal transfer sheet 1)
Using a biaxially stretched polyethylene terephthalate film (hereinafter referred to as PET) having a thickness of 4 μm as a substrate (trade name: manufactured by Lumirror Toray), a back layer coating liquid having the following composition is used as one of the back layers. The back layer was formed by applying and drying by a gravure printing method so that the application amount was 0.06 g / m ² . Next, on the surface opposite to the back layer of the substrate on which the back layer is formed, the transfer release layer coating liquid 1 having the following composition is gravure so that the coating amount when dried is 0.4 g / m ^2. It was applied and dried by a printing method to form a transferable release layer. Then, the transfer peeling layer on the transferable protective layer coating solution having the following composition, coating with a gravure printing method as the coating amount after drying is 0.2 g / m ^2, dried, transferred A protective layer was formed. Subsequently, a transferable colored layer coating solution having the following composition was applied onto the transferable protective layer by a gravure printing method so that the coating amount at the time of drying was 0.7 g / m ² , and then carried out. The thermal transfer sheet 1 of Example 1 was formed.

<Coating liquid for back layer>
・ Acrylic modified silicone 10 parts by mass (polyalloy NSA-X55, manufactured by NATCO Corporation)
Silicone isocyanate 2 parts by mass (Diaroma SP901, manufactured by Dainichi Seika Kogyo Co., Ltd.)
・ Methyl ethyl ketone 20 parts by mass ・ Toluene 20 parts by mass

<Transferable release layer coating solution 1>
Carnava wax 75 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
-Zinc stearate 15 parts by mass (Hi-micron F-930, manufactured by Chukyo Yushi Co., Ltd., melting point 120 ° C., average particle size 0.9 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

<Coating liquid for transferable protective layer>
80 parts by mass of a cyclic olefin polymer having a structural unit derived from a norbornene monomer (Arton G 7810, manufactured by JSR Corporation, glass transition temperature: 165 ° C.)
20 parts by mass of incompatible resin (acrylic polyol resin) for the cyclic olefin polymer (Thermolac SU100A, manufactured by Soken Chemical Co., Ltd.)
-Polyethylene WAX 5 parts by mass (slip agent B, manufactured by Showa Ink Industries, Ltd.)
-Mixed solvent of toluene and methyl ethyl ketone (mixed at a mass ratio of 1: 1) 100 parts by mass

<Coating liquid for transferable colored layer>
-Phenol resin (solid content: 50%) 2.40 parts by mass (phenol novolac resin, TD-2090, manufactured by DIC Corporation, softening point 118-122 ° C)
-Carbon black (solid content: 35%) 2.29 parts by mass-Mixed solvent of toluene and methyl ethyl ketone (mixed at a mass ratio of 1: 1) 5.31 parts by mass

( Reference Example 2: Production of thermal transfer sheet 2)
Reference Example 2 was carried out in the same manner as Example 1 except that the transferable release layer coating solution 2 having the following composition was used instead of the transferable release layer coating solution 1 in the thermal transfer sheet of Example 1. Thermal transfer sheet 2 was obtained.
<Transferable release layer coating solution 2>
Carnauba wax 80 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
・ Zinc stearate 10 parts by mass (Hi-micron F-930, manufactured by Chukyo Yushi Co., Ltd., melting point 120 ° C., average particle size 0.9 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

(Example 3: Production of thermal transfer sheet 3)
Example 3 was the same as Example 1 except that the transferable release layer coating solution 3 having the following composition was used in place of the transferable release layer coating solution 1 in the thermal transfer sheet of Example 1. The thermal transfer sheet 3 was obtained.
<Transferable release layer coating solution 3>
-Carnauba wax 70 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
・ Zinc stearate 20 parts by mass (Hi-micron F-930, manufactured by Chukyo Yushi Co., Ltd., melting point 120 ° C., average particle size 0.9 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

( Reference Example 4: Production of thermal transfer sheet 4)
Reference Example 4 was carried out in the same manner as in Example 1 except that the transferable release layer coating solution 4 having the following composition was used in place of the transferable release layer coating solution 1 in the thermal transfer sheet of Example 1. The thermal transfer sheet 4 was obtained.
<Transferable release layer coating solution 4>
Carnava wax 63 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
・ Zinc stearate 27 parts by mass (Hi-micron F-930, manufactured by Chukyo Yushi Co., Ltd., melting point 120 ° C., average particle size 0.9 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

( Reference Example 5: Production of thermal transfer sheet 5)
In the thermal transfer sheet of Example 1, Reference Example 5 was carried out in the same manner as Example 1 except that the transferable release layer coating solution 5 having the following composition was used instead of the transferable release layer coating solution 1. A thermal transfer sheet 5 was obtained.
<Transferable release layer coating solution 5>
-Carnauba wax 70 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
・ Zinc stearate 20 parts by mass (Hydrin Z-7-30, manufactured by Chukyo Yushi Co., Ltd., melting point 120 ° C., average particle size 5.5 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

( Reference Example 6: Production of thermal transfer sheet 6)
A thermal transfer sheet 6 of Reference Example 6 was obtained in the same manner as in Example 1 except that the transferable protective layer was not formed in the thermal transfer sheet of Example 1.

(Comparative Example 1: Production of comparative thermal transfer sheet 1)
In the thermal transfer sheet of Example 1, a comparative example was made in the same manner as in Example 1 except that instead of the transferable release layer coating solution 1, a comparative transferable release layer coating solution 1 having the following composition was used. 1 comparative thermal transfer sheet 1 was obtained.
<Comparative transfer layer coating solution 1>
Carnava wax 63 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
Fatty acid amide 27 parts by mass (Hi-micron L-271, manufactured by Chukyo Yushi Co., Ltd., melting point 100 ° C., average particle size 0.4 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

(Comparative Example 2: Production of comparative thermal transfer sheet 2)
In the thermal transfer sheet of Example 1, a comparative example was made in the same manner as in Example 1 except that instead of the transferable release layer coating solution 1, a comparative transferable release layer coating solution 2 having the following composition was used. 2 comparative thermal transfer sheet 2 was obtained.
<Comparative Transferable Release Layer Coating Solution 2>
Carnava wax 63 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
-Polyethylene wax 27 parts by mass (Polylon L-788, manufactured by Chukyo Yushi Co., Ltd., melting point 102 ° C., average particle size 0.1 μm)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

(Comparative Example 3: Production of Comparative Thermal Transfer Sheet 3)
In the thermal transfer sheet of Example 1, a comparative example was made in the same manner as in Example 1 except that instead of the transferable release layer coating solution 1, a comparative transferable release layer coating solution 3 having the following composition was used. 3 comparative thermal transfer sheet 3 was obtained.
<Comparative Transferable Release Layer Coating Solution 3>
Carnava wax 63 parts by mass (WE-95, manufactured by Konishi Co., Ltd., melting point 86 ° C.)
-Paraffin wax 27 parts by mass (WE-65, manufactured by Konishi Co., Ltd., melting point 75 ° C.)
Latex 10 parts by mass (Nippol LX430, manufactured by Nippon Zeon Co., Ltd.)
-Mixed solvent of water and isopropyl alcohol (mixed at a mass ratio of 1: 1) 100 parts by mass

(Comparative Example 4: Production of comparative thermal transfer sheet 4)
In the thermal transfer sheet of Example 1, in comparison with Comparative Example 4 in the same manner as in Example 1 except that instead of the transferable coloring coating solution, a comparative transferable colored layer coating solution having the following composition was used. A thermal transfer sheet 4 was obtained.
<Coating liquid for comparative transferable colored layer>
Acrylic resin 1.20 parts by mass (BR-79 manufactured by Mitsubishi Rayon Co., Ltd., Tg 35 ° C., Mw 70000)
-Carbon black (solid content: 35%) 2.29 parts by mass-Mixed solvent of toluene and methyl ethyl ketone (mixed at a mass ratio of 1: 1) 5.31 parts by mass

[Evaluation of thermal transfer sheet]
(1) Printability evaluation Each thermal transfer sheet obtained in Examples 1 and 3, Reference Examples 2, 4, 5 and 6, and Comparative Examples 1 to 4, and a laminated film of nylon / low density polyethylene (thickness 100 μm, A thermal head with a resolution of 300 dpi according to the printing conditions (Heat Adjust: +0, Printer Speed: 10IPS) using a melt transfer type thermal transfer printer (manufactured by B-SX4T TEC), superposed on the nylon side of DNP) Printed a 1-dot character pattern. Further, the printability was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
<Evaluation criteria>
A: Printing is good visually.
B: The printed matter has a missing part or a crushed part, but it can be read.
C: The printed matter has a missing part or a crushed part and cannot be read.

(2) Evaluation of boil resistance 10% of each printed matter formed using the thermal transfer sheets of Examples 1 and 3, Reference Examples 2, 4, 5, and 6 and Comparative Examples 1 to 4 in boiled hot water. After leaving for a minute, the surface of the printed material was rubbed 20 times with a paper waste. Thereafter, the printed matter was visually observed, and the boil resistance was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.
<Evaluation criteria>
A: There is no change in the printed matter.
B: The part which is missing from the printed matter was peeled off, but it was legible.
C: The part which is missing from the printed matter is peeled off and cannot be read.
D: The printed matter disappears completely.

(Summary of results)
In the thermal transfer sheets obtained in Examples 1 and 3 and Reference Examples 2, 4, 5 and 6 , the transferable release layer includes a wax having a melting point of 65 ° C. or higher and a metal soap, and the transferable colored layer is colored. Since the printing agent and the phenol resin having a softening point of 100 ° C. or higher were included, the printed material had excellent boil resistance while having good printability. Further, when Example 1 and Reference Example 6 were compared, it was revealed that Example 1 provided with the transferable protective layer was particularly excellent in the boil resistance of the printed matter.
On the other hand, the thermal transfer sheets obtained in Comparative Examples 1 to 3 were inferior in the boil resistance of printed matter because the transferable release layer did not contain metal soap.
The thermal transfer sheet obtained in Comparative Example 4 was inferior in boil resistance and printability of the printed matter because the transferable colored layer did not contain a phenol resin having a softening point of 100 ° C. or higher.

DESCRIPTION OF SYMBOLS 1 Base material 2 Transferable peeling layer 3 Transferable colored layer 4 Back surface layer 5 Transferable protective layer 10 Thermal transfer sheet

Claims (2)

On one surface of the substrate, at least a transferable release layer and a transferable colored layer are disposed in this order from the substrate side, and a back layer is disposed on the other surface of the substrate,
The transferable release layer includes a wax having a melting point of 65 ° C. or more and a metal soap, the average particle diameter of the metal soap is 0.1 to 2.0 μm, and the content of the metal soap is the transfer 15 to 25% by mass with respect to the total solid content contained in the adhesive release layer,
Said transferable color layer seen containing a colorant and a softening point 100 ° C. or more phenolic resins,
A transferable protective layer is further disposed between the transferable release layer and the transferable colored layer, and the transferable protective layer protects the cyclic olefin polymer having a glass transition temperature of 100 ° C. or higher. A thermal transfer sheet containing a solid content exceeding 50% by mass of the layer and further containing an incompatible resin for the cyclic olefin polymer . Wherein the metal soap is zinc stearate, thermal transfer sheet according to claim 1.

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